The present invention relates to a self adhesive tape of the type commonly referred to as duct tape, and a method of fabricating same.
Duct tape is conventionally fabricated by a process as illustrated in FIG. 1, and wherein a sheet of black or otherwise colored plastic film is printed on one side with product information, or other indicia. In order to facilitate the adherence of the printing to the surface of the sheet, the surface which receives the printing may be initially corona or otherwise treated to provide a roughened xe2x80x9chigh energyxe2x80x9d surface. After printing, the opposite side of the sheet is coated with an adhesive, which may include an embedded mesh fabric reinforcement. Also, in some instances, the back side of the sheet may also be xe2x80x9cbump treatedxe2x80x9d as known in the art to improve the adherence of the adhesive coating. Finally, the sheet is slit and wound into rolls, with the print on the outside of the winds and the adhesive on the inside of the winds.
While duct tape as constructed above is in widespread use, difficulties have been encountered in permanently adhering the adhesive coating to the back side of the sheet, and delamination often occurs when the roll is unwound, particularly when the roll has been subjected to relatively high heat. Also, with the adhesive coating directly engaging the printing on the adjacent wind of the role, the printing can be disfigured during the unwinding operation.
It is an object of the present invention to provide an improved self adhesive tape of the type described above, and which avoids or at least significantly alleviates the above noted problems.
The above and other objects and advantages of the present invention are achieved by the provision of a self adhesive tape which comprises a substrate formed of a clear plastic sheet, and which has reverse printing applied to one side only of the sheet so that the reverse printing is visible as a positive image when viewed through the other side of the sheet. A flood coating of ink is applied to the printed side of the sheet so as to substantially cover the reverse printing, and a coating of an adhesive is applied so as to substantially cover the flood coating. The side of the sheet which receives the printing may be initially treated so as to roughen or xe2x80x9cenergizexe2x80x9d its surface and thereby promote the adherence of the printing and the flood coating thereto. As final steps, the sheet may be slit to form a plurality of separate tapes, which are each then wound upon itself to form a roll, with the adhesive coating directly contacting the untreated back side of the sheet. Also, the rolls are preferably wound so that the clear sheet is on the outside of the winds, with the printing and adhesive on the inside of the winds.